This invention related to molding a tire bead and especially to curing the rubber coating on the bead wires of a bead bundle which is held in a predetermined shape. The bead wires are held in place during the vulcanization so that when the bead ring is placed in a mold for injection molding of an apex on the bead, the mold will not be damaged by out of place wires. The bead bundle is also cured in a circular shape so that problems with pinching out of round beads are avoided during the closing of the bead apex mold.
Heretofore as shown and described in U.S. Pat. No. 5,798,127, a bead bundle of rubber coated bead wires has been placed in an apex mold and held in position by blades engaging the radially inner surface of the tire bead bundle. The apex-bead assembly is then formed by injection of rubber into the apex mold cavity of the apex mold. If the bead wires extend outwardly from the bead bundle, the mold may be damaged during closing causing shut down and costly repairs. With this method the unvulcanized bead bundle may be changed in shape by handling before placing in the apex mold. Also the bead bundle may be distorted and come apart during the injection process when rubber is being injected past the bead at high velocity and with great force.
Another object of the present invention is to provide a bead curing finger mold further characterized by the upper fingers and the lower fingers having sloped edges for guiding and compressing the bead bundle in a central position upon closing of the mold.
Another object of the present invention is to provide a bead curing finger mold further characterized by the upper fingers and the lower fingers having molding surfaces providing a circular molding member surface of the mold with a precise predetermined diameter of the bead bundle upon closing of the mold.
Another object of the present invention is to provide a bead curing finger mold wherein the bead bundle is a tire bead having a plurality of wires wrapped in a the bead bundle and coated with an elastomeric material further characterized by means for heating the mold for vulcanizing the elastomeric material.
Another object of the present invention is to provide a bead curing finger mold further characterized by the upper fingers and the lower fingers having extensions extending beyond the molding surfaces for guiding the bead bundle and providing recesses for receiving the extensions in the closed condition of the mold.
Another object of the present invention is to provide a bead curing finger mold further characterized by the lower finger mold half being raised to close the mold and the upper finger mold half has spaced apart spring loaded ejector fingers for retracting upon closing of the mold and for extension upon opening of the mold to transfer the bead bundle to the lower finger mold half.
Another object of the present invention is to provide a bead curing finger mold further characterized by the lower mold half having circumferentially spaced apart ejectors and bead holders extending upwardly through the lower finger mold half for holding the bead bundle in the lower position of the lower finger mold half prior to closing of the mold and ejecting the bead bundle upon lowering of the upper mold half after vulcanization of the bead bundle.
In U.S. Pat. No. 5,262,115, an apex bead assembly mold for injection molding the apex assembly is shown where the rubber coated bead bundles are held in place on a cylindrical core by spaced-apart coaxial round rings arranged in side by side relation and engaging the axially extending inner surfaces and the radially extending inner surfaces of the beads so that when half molds are mounted around the core with the beads held in place, apex portions may be injection molded. Thereafter, the mold halves are removed and the bead apex assemblies pulled off the rings. During the injection process the unprotected bead bundle of unvulcanized rubber may be distorted or come apart due to high velocity movement of the rubber past of the bead.
This invention relates to a mold for heating and enclosing a circular member comprising a first mold member, a second mold member movable into engagement with the first mold member to provide a mold cavity characterized by the first mold member having a plurality circumferentially spaced first fingers, the second mold member having a plurality of circumferentially spaced second fingers movable into meshing engagement with the first fingers upon closing of the mold by movement of the first mold member towards the second mold member providing a circular mold cavity for the circular member.
This invention further relates to a bead curing finger mold characterized by a plurality of circumferentially spaced lower fingers disposed in a lower ring, a plurality of circumferentially spaced upper fingers disposed in an upper ring, the lower ring being positioned in a generally horizontal position for supporting a bead bundle, and the upper ring being positioned over the lower ring with the lower fingers interposed between the upper fingers in a closed position of the mold for containing and guiding the bead bundle and providing spaces along the lower fingers and the upper fingers to accommodate variations in size of the bead bundle.
This invention is also directed to the construction of a tire bead comprising multiple revolutions of metal wires coated with rubber and wound in a circular configuration to form a bead bundle characterized by the bead bundle being cured in a bead curing finger mold having a plurality of circumferentially spaced lower fingers disposed in a lower ring in a generally horizontal lower position for supporting the bead bundle, a plurality of circumferentially spaced upper fingers disposed in a generally horizontal upper ring positioned over the lower ring with the lower fingers interposed between the upper fingers in the closed position of the mold for containing and guiding the wires of the bead bundle and providing spaces along the lower fingers and the upper fingers to accommodate variations in size of the bead bundle during vulcanization of the bead upon application of heat to bead curing finger mold.